Southwest Airlines (SWA) on Monday announced its pilots, represented by the Southwest Airlines Pilots’ Assn. (SWAPA) and Air Tran pilots, represented by the Air Line pilots Assn. (ALPA), have ratified a seniority integration agreement. The agreement combines the merging airlines’ pilot seniority lists.

“The ratification of this seniority integration agreement is a significant milestone in the integration of our two great airlines, and wouldn’t have been possible without the leadership of our company’s negotiating committee bringing all parties together,” said SWA EVP and CEO Mike Van de Ven.

According to SWA, there is still work to be done to integrate the more than 6,000 SWA pilots and 1,700 AirTran pilots. “Integration teams made up of pilots from both groups have already been formed and are moving forward in an effort to make the combining of the two groups as seamless as possible,” SWA said.